A laser beam is traveling through an unknown substance. When it encounters a boundary with air, the angle of reflection is 27.9° and the angle of refraction is 39.0°.
(a) What is the index of refraction of the substance?
________
(b) What is the speed of light in the substance?
_______m/s
(c) At what minimum angle of incidence would the light be totally internally reflected?
_______°